This invention relates to emergency telephone systems, and particularly to a portable emergency system useful in situations where control over a telephone line has to be exercised, yet in which it must be possible to accord privacy to the user of the line.
Law enforcement agencies are frequently confronted with a situation in which a lawbreaker has barricaded himself in a particular location, and it is impractical for the police to enter that location for an arrest either because the lawbreaker is holding hostages or because he has control over explosives or is otherwise armed in such a way as to make direct capture unadvisable. In such a situation, it is often necessary for a negotiator to be able to communicate with the lawbreaker from a nearby location. Inasmuch as most houses are equipped with a telephone, such a means of communication is usually readily available to the lawbreaker. The problem is that, for an effective handling of the situation, it is necessary for the negotiator to not only exercise control over outside communications to and from the lawbreaker, but also to enable the lawbreaker to hold private conversations upon request, as for example with his attorney.
Present methods of lawbreaker-negotiator communications normally rely on wire taps and are consequently unsatisfactory in both respects.